Integrated circuits are employed in most of the digital appliances utilized on a daily basis by consumers. Integrated circuits may refer to an electronic circuit built onto a single piece of substrate, a chip, and enclosed within a package. Integrated circuits generally perform a desired function or plurality of functions. In the fabrication of integrated circuits, bondpads are employed to form the connection from the integrated circuit to the package. A package may refer to the housing of the chip and electrically interconnects the chip with outside circuitry.
Referring to FIG. 1, an embodiment of an integrated circuit 100 known to the art is shown. An integrated circuit 100 may include a silicon substrate layer 110 with multiple dielectric layers 120–140 and multiple metal layers 150–170. The bondpad 180 may refer to the top layer of metal and allows a connection from the integrated circuit to the package, a package pin for example.
Capacitance occurs between the bondpad 180 and the other metal layers 150–170. The amount of capacitance is typically proportional to the area of the bondpad 180 and increases as the distance between the bondpad 180 and the metal layers 150–170 decreases. A drawback caused by the capacitance associated with the bondpad 180 is a reduction in circuit performance. As operating speeds have increased, circuit performance has been further reduced by the capacitance associated with the bondpad.
Conventional solutions to reducing the capacitance associated with the bondpad have involved the modification of the layer structure of the integrated circuit. However, modification of the layer structure is expensive and typically causes reduced reliability of the circuit. Further, this type of capacitance reduction only provides a minimal reduction in capacitance. Consequently, an improved apparatus and system for reducing the bondpad capacitance of an integrated circuit is necessary.